DC-10Khz frequency-voltage converter

The converter generates an output voltage which is linearly proportional to the input frequency waveform. Each zero crossing at the comparator`s input causes a precise amount of change to be dispensed into the op amp`s summing junction. This charge in turn flows through the feedback resistor generating voltage pulses at the output of the op amp

Capacitor (Cint) across Rint averages these pulses into a dc voltage which is linearly proportional to the input frequency.